Very high dynamic range image sensors are key to solving many problems in a multitude of areas including automotive sensing, machine vision, professional video, scientific imaging, and others. Automotive imaging applications are particularly demanding. There are often very wide dynamic range scenes which include outdoor sunlit scenes, transitions to dark areas such as tunnels and tree canopy-lined streets, bright LED lights which introduce distracting flickering in scene captures, etc.
One class of solutions utilizes multiple exposures having different exposure times to generate a high dynamic range image. However, the resulting scene can suffer from motion blur.
Another class of solutions relies on multiple photodiodes in each pixel in which the photodiodes have different light conversion efficiencies. Such multiple photodiode systems suffer from different spectral responses between the photodiodes, and hence, providing a high dynamic range output by converting the individual photodiode responses and combining the responses poses significant challenges.